' " 22409-6014-RU-00 ,

, ;

!

STUDYOF MONOPROPELLANTS' FOR ELECTROTHERMALTHRUSTERS . --

,. EVALUATION TEST PROGRAM TASK SUMMARY REPORT

: lJ.D. Kuenzly

' TRW Systems Group 4)j.' .,'_ One Space Park i, Redondo Beach, Calif. 90278

: MARCH 1974 _

INTERIM REPORTFOR PERIOD .__

AUGUST 1973 - FEBRUAR_ 1974 ;,_

, _ ./.,. _._

, /f "}ODDARD SPACE FLIGHT CENT_ '_':'_,_t_/,.,_'O,.'.%-_

Greenbelt, Maryland 20771 _-_ '., _,

(NASA-CR-139072) STUDY OF MONOPROPELLAN'2S N74-32216 mFOB ELECTRG_HER_AL THRUS_EBS. EVALUATION

TEST PROGRA_ TASK SU_:_ARY REPORT

t Interim Ee_o_t, Auq. I_73 - Feb. (TR_ Unclas

Systems Group) 8_ p _IC $7.25 CSCL 21I G3/27 _7_29

]974024]03

https://ntrs.nasa.gov/search.jsp?R=19740024103 2018-08-30T03:28:17+00:00Z

22409-6014-RU-00 '_'_

STUDYOF MONOPROPELLANTS _?

•/ FOR ELECTROTHERMALTHRUSTERS iI_

' . EVALUATION TEST PROGRAM TASK SUMMARY REPORT __

l iJ.D. Kuenzly

"'_! TRW Systems GroupI

_" One Space ParkRedondo Beach, Calif. 90278

} MARCH 1974

I

INTERIM REPORTFOR PERIOD

, AUGUST 1973 - FEBRUARY 1974

!,f

_" Prepared for

i GODDARD SPACE FLIGHT CENTER_ Greenbelt, Maryland 20771ID!,

_,_ i

ii

197402410:3-002

I. Report No. [ 2. Government Accession No. 3. Rec_plent's Catalog No.22409-6014- RU-00 i

4. Title and Subtltle 5. Report DateStudy of Monopropellantsfor ElectrothermalThrusters. March 1974EvaluationTest ProgramTask SummaryReport

6. Perfcrmtn8 Organization Code2

7. Author(s) 8. Performing Organization Report No. '_J. D. Kuenzly 22409-6014-RU-00 l

i9. Performing Organization Name and Address I0. Work Unit No. .

TRW Syste_.sGroupOne Space Park II_RedondoBeach, California 90278 11. Contract or Cramt No.

NAS5-23202 i!12. Sponsoring &gency Name and Address 13. Type of Report and Period Covered _ "

GoddardSpace F11ghtCenter InterimReport ]!

- Greenbelt,Maryland20771 August1973-February1974 _)

: R. Callens - Technical Monitor i4. Sponsoring Agency Code

IS. Supplementary Notes

: _ Preparedunder the directionof C. K. Murch,ProgramManager

i

ii 16. Abstract

! • ,_,nelectrothermalthrusterdesignedfor operationwlth MIL-gradehydrazineis suitable; for operation with propellants having lower freezing points. These propellants are 76%t hydrazine- 24% hydrazineazide, Aerozlne-50,50% _drazlne - 50% monomethylydrazine,anu' ' a Till-formulated mixtureof 35% hydrazine- 50% monomethylhydrazine- 15% ammonia. A

,: steady-state specific impulse of 200 sec was exceeded by all propellants. A pulse-modevalue of 175 sec specific impulse was exceeded by the aztde blend for pulse widths greaterthan 50 ms and was met by the carbonaceous propellants for pulse widths greater than 100 ms.Longer residence times were required for the carbonaceous propellants; the original thrusterdesign was modified by increasing the characteristic chamber length and density of screenpacking. A substantial amount of thermal energy must be supplied to initiate decompositionof propellants containing unsymmetrtcal-dtmethylhydraztne and monomethylhydraztne. The ratecontrolling factor appeared to be the endothermtc removal of methyl radicals. Carbondeposition was minimal with the TRW-formulated mixture whereas that observed with Aerozine- _.50 may pose problems for long term operation. The original baseline thruster configuration -.gave non-opttml hydrazine performance. Performance was increased by promoting homogeneous,gas-phase decomposition kinetics in a larger head space. Methods of increasing residencetimes in the head space should be investigated for the carbonaceous propellants. Alternateinjection techniques which could produce an _amized spray appear desirable. The largehead space thruster which gave superior performance with hydrazine should be fully exploited.

• 17 Key Words (Selected by _ 18. O£etr:Lbutlon Statement _ '__onopr._pelI ant _ _"Electrothermal _ ,,_Thruster _ _';_,

Hydraztne Substitutes _ _ _'

-y. security Classlf. J20. Security--. ]21_--_o of ?qss 22. Prlce* pl• Unclassified [ Unclassified ---------- i_iil e•For sale by the Clearinghouse for Federal Scientif_Lc and Technical Informtton,

Springfield, Vir_4nta 22151. ttm

1974024103-003

PREFACE

bThe objectiveof the "Studyof Monopropellantsfor Electrothermal

.( Thrusters"programis to determinethe feasibilityof operatingsmallthrust •

levelelectrothermalthrusterswith monopropellantsotherthan MIL-grade

hydrazine. The work scope includesanalyticalstudy,designand fabrication

of demonstrationthrusters,and an evaluationtestprogramwhereinmono-

: propellantswith freezingpointslowerthan MIL-gradehydrzzineare evalua-

" ted and characterizedto determinetheir applicabilityto electrothermal _")

i thrustersfor spacecraftattitudecontrol.• &

The electrothermalthrusterdesignedfor operationwith MIL-grade

hydrazineis suitablefor operationwith propellantshavingIcwer freezing

• points. These propellantsare 76% hydrazine- 24% hydrazineazide,

Aerozine-SO,50% hydrazine- 50% monomethylhydrazine,and a TRW-formulated

i mixtu,.-_of 35% hydrazine- 50% monomethylhydrazine- 15% ammonia. The

i :"; programgoal of 200 sec steady-statespecificimpulsewas exceededby all

. propellants.The pulsed-modeprogramgoal of 175 sec was exceededby the

,• azideblend for pulsewidthsgreaterthan 50 ms and was met by the carbona-

"-! ceous propellantsfor pulse widthsgreaterthanlO0 ms ,_i •

" Longerresidencetimeswere requiredfor the carbonaceouspropellants;

i , the originalthrusterdesignwas modifiedby increasingthe characteristic

" t chan_oerlengthand densityof screenpacking• A substantialamountof

• thermalenergymust be suppliedto initiatedecompositionof propellants I ")

) containingunsymmetrical-dimethylhydrazineand monomethylhydrazine.The

I ; Prate controllingfactorappearedto be the endothermicremovalof methyl

, radicals.

,, - Carbondepositionwas minimalwith the TRW-formulatedmixturewhereas

" _ thatobservedwith Aerozine-50may pose problemsfor long termoperation•

'i _, The originalbaselinethrusterconfigurationgavenon-optimalhydrazine

I :_Z performance Performancewas increasedby promotinghomogeneous,gas-phase

I" decomposit,unkineticsin a largerhead space..... III

197402410:3-004

Methods of increasing residence times in the head space sho:Id be

investigated for tF:e carbonaceous propellants. Alternate injection tech-

niques which could produce _n atomized spray appear desirable. The large|

head space thruster which gave superior perfomance with hydrazine should

be fully exploited,

"

TABLE OF CONTENTS

].0 INTRODUCTION...............................................l

2.0 EVALUATIONTEST PROGRAM....................................2

2.1 DESCRIPTION...........................................2 "_

2.1.1 Propellants....................................22.1.2 Thruster.......................................22 l 3 Test Methods 2 "e • e i o e bo el ! • e. Ioii ee ,. me .e el i | _me e o e e

2,2 CHEMICALANALYSES.....................................8I

2.3 BASELINEPERFORMANCEDATA .............................Ig

' 2 4 PROPELLANTCHARACTERIZATION 23• lb..l• • leo I Jlelel, .,_ 0• _•e.

2.4.1 Hydrazine-HydrazineAzide ......................304 2.4.2 Aerozine-50....................................37

2 4 3 Monomethylhydrazine 37• • . ace•eli o,ee o• CO,.O• ••,• it •,,I

2.5 PERFORMANCEOPTIMIZATION..............................44

1 2.5.1 Hydrazine-HydrazineAzide ......................44i 2.5.2 Aerozine-50....................................46

} 2.5.3 Monomethylhydrazine ............................ 532.5.4 Mixture of Hydrazine Monopropellants ........... 55

_'_ 3 0 DISCUSSIONOF RESULTS 62I • ,•o _•o••e•o ••.,le •••eto,•ee•_e•toa••t•

s 3 1 BASELINEPERFORMANCE 62" • ••o•, Q• •l,e bo •tee,e ,• ot el oo o•,•_te

3 2 CANDIDATEMONOPROPELLANTS 64• •o e • o •61• e •e eo l• b• •e _e ee ele_

i4.0 NEW TECHNOLOGY............................................69

! 5.0 PROGRAMFORTHENEXTREPORTINGINTERVAL ................... 70 _ "

6,0 CONCLUSIONS............................................... 71

_ 7 0 RECOMMENDATIONS 73

., 8.0 REFERENCES................................................74

!t "

I

i 974024 i 0:3-006

q

LIST OF FIGURES

Page

I. Monopropellant Demonstration Thruster ....................... 3 I

2. Sea-Level Test Schematic ............. 4leoleiioIDi _i,,imooe,ml

3. Mixture of Hydrazine Monopropellants (MHM) Piston Tank ...... 5

I 4. Sea-Level Thruster-Valve Configuration ..................... 7 _ •

5. Vacuum Chamber Test Appara:us .............................. 9"i

,_ 6. Thruster Mounted for Performance Measurements .............. I0

7. Propellant Supply System ................................... II:=

8. Data Acquisition Equipment ................................. 12

i 9. Baseline Pulsed-Mode Characteristics ....................... 20

lO Baseline Pulsed-Mode Performance 21• ioQetletQeooeii*,oeoe_JQ•tlt ;

!I

;_ II. Baseline Steady-State Performance ......................... • . 22

12. Deposit on Top Platinum Screen ..............................24I

, 13. Haynes 25 Retaining Screen .................................. 25w-

_ 14. Backscattered Electron Image of the Top Platinum Screen_ Center ......................................................26

i I 15. Iron K_ X-ray Image of the Top Platinum Screen Center ....... 28 ""t

_ 16. Preliminary Sea-Level Steady-State Operation With 76Percent Hydrazine-24 Percent Hydrazine Azide ................ 31 ;

17. Steady ,StateOscillograph Chamber Pressure Traces at, Times Corresponding to Those of Figure 16 ................... 32

I:_, 18. OscillGgraph Trace of Chamber Pressure Prior to and at "

Injector Failure ............................................33 '_/..

'i : lg. Injector Failure ...........................................34 _,

20. Post-Test Condition of Screen Pack From Thru=ter Operated: on 76 Percent Hydrazine - 24 Percent Hydrazine Azide ........ 35

1974024103-007

LIST OF FIGURES (Continued)

Page

21. Downstream Thrust Chamber Components of Thruster Operated ..on 76 Percent Hydrazine - 24 Percent Hydrazine Azide ....... 36

"

22. Backscattered Electron Image of the Top Platinum ScreenCenter From Thruster Operated With Hydrazine-Hydrazine mw_Azide ....................................................... 38

23. Iron K X-ray Image of the Top Platinum Screens of Figure _...: 22 . _ 39• •latlleoloJJiJeeQoii1etelowlooeeeQoeltlgwmel,oleoloteoleL

i _ 24. Preliminary Sea-Level Steady-State Thruster Operation With' Aerozine-50 ................................................. 40

: 25. Aerozine-50 Post Test Screen Pack Appearance ................ 41

4 26. Preliminary Sea-Level Steady-State Thruster Operation With _-Monomethyl Hydrazine 42• ,,,oo•ee,•,•,e_aelelIIoiie_e_eelgleet_o_

t

1 27. Hydrazine-Hydrazine Azide Steady-State Performance .......... 47

el , 28. Hydrazine-HydrazineAzide Pulsed-Mode Perfor_._nce........... 48

; _ 29. Post-Test Appearance of Nozzle Section From Thruster Operated

. ( 30 Minutes Steady-State With Aerozine-50 .................... 50!f : 30. Steady-State Performance Measurements With Aerozine-50 ...... 51_."

31. Pulsed-Mode Performance Measurements With Aerozine-50 ....... 52

32. Aerozine-50 Pulsed-Mode Analog Data Recording ............... 54

'_Ii_ dy Hyd Withi 33. Stea -State Performance of razine Long Screen

Packs ......................................................57

• ._ 34. Thruster Temperature Distributions With Long Screen Packs ... 58

" 35. MHMSteady-State Performance With 1.02 cm Screen Pack 59', _ eeoc61•

_/" 36. _M Stead_-State Performance With 2.54 cm Screen Pack ....... 60

37. Steady-State Performance Data of Five Candidate Monopropel- :vlants .......................................................65

38. Pulsed-Mode Performance Data of Four Candidate Monopropel-lants .......................................................66 _.,

vii --

i 974024 i 0:3-008

|

Q

LIST OF TABLES

|

I. Analysis of MIL-grade Hydrazine Propellant ................. 14 '-..

"_ 2. Analysis of Aerozine-50 Propellant (50% N2H4 - 50% UDMH) ... 15 ,

3. Analysis of r,lonomethylhydrazinePropellant ................. 16

4. Analysis of Hy._razine-Hydrazine Azide Propellant ........... 17

_, 5. Analysis of Anhydrous Ammonia .............................. 18 _'

.! _ 6. Spectral Analysis of Platinum Screen Deposit ............... 27

7. Nominal Compositions of Stainless Steels and Haynes 25 ...... 29

8. Configurational Hydrazlne Performance Data (Steady-State) ... 63

I 9. Comparison of Pulse-Mode to Steady-Std_e Specific Impulse .. 67v

i

1 ',,

!( .l

1_ ,m _

;X

i'!

viii

•_a. ,

] 974024 ] 0:3-009

1.0 INTRODUCTION

This report presents the evaluation test program results performed in

support of the "Study of Monopropeilants for Electrothermal Thrusters." _The test program was conducted to evaluate and characterize the applicability

of low freezing point monopropellants to electrothermal thrusters for space-

craft attitude control. The work performed during this program period

included the initial steady-state characterization of four candidate mono- _-_

propellants with thrusters designed and baseline tested for operation with

MIL-grade hydrazine; an optimization phase wherein the thruster configuration _...was changed to meet the specific requirements of each propellant. Simulated

high altitude performance measurements were obtained for the optimized

thruster configurations and compared to operation with MIL-grade hydrazine.

Each propellant utilized was subjected to a chemical analysis.

This report presents the characterization and optimization test results, _

" propellant chemical analyses, and describes the test methods and data acqui-

sition equipment used in obtaiping the performance measurements. _'

I,

-w

1974024103-010

2.0 EVALUATIONTEST PROGRAM

2.1 DESCRIPTION

2.1.I Propellants b

Fivepropellantsotherthan MIL-gradehydrazinewere evaluatedduring"

the test programphase. Theywere monomethylhydrazine(MMH)and a 50-50 .

mixtureof MMH and hydrazine,Aerozine-50(AERO-50),76% hydrazine- 24% _-

hydrazineazide (HA),and TRW-formulatedmixed hydrazinemonopropellant

of 35% hydrazine- 50% monomethylhydrazine- 15% ammonia(MHM). These pro-

,' pellantswere selectedas low freezingpoint substitutesfor MIL-gradeh_dra-

_ zine thatdo not requirean excessivetrade-offbetweenfreezingpoint and' performance.A separateanalyticalstudiesreport(1) describesthe criteria

used in recommendingthe above propellants.

2.1.2 Thrustert

A _chematicof the initialdemonstrationthrusterconfigurationis

shownin FigureI. The thrusterdesignwas basedon the Electrothermal

e_. HydrazineThruster(EHT)developedby TRW for NASA/GSFCon NASA Contract

(! ' No. NAS5-I1477.(2) The currentthrusterdesignand fabricationphaseis

I"I, describedin an earlierreport.(3)

": 2.1.3 Test Methods

i" _ Preliminaryperformancetestswith threeof the fivecandidatepropel-

(__ lantswere performedat the TRW SystemsGroup CapistranoTest Facility.I

'_ Simulatedhigh altitudeperformancemeasurementswere conductedat the

I >maintest facilityin RedondoBeach. Propellantchemicalanalyseswere _.

_ performedat both test facilities.The specificrequirementsfor the

•_i i: EvaluationTestProgramwere presentedin an earlierreport.(1) _

i The preliminarysea-levelmeasurementswere performedusing the equip- "

, ment shown schematically4, Figure2. The propellantsMMH,AERO-50,and _<

_,_.: HA were suppliedin 500 cc "nterchangeableType 304 stainlesssteelsample ":'C

cylinders. A separatepistontank (Figure3) was requiredto preventthe ,.'_

loss of ammoniafrom the MHM blend. Two additional.-ylindersof water and

alcoholwere incorporatedin the propellantsupplymanifold. Thisenabled

the convenientflushingand cleaningof the thrustervalveand propellant

1974024103-011

1974024103-012

I z I | _'_._[---_----" ,i •

_lill

Iiii I _ r + ,, ' i' i, - I' , _,I_I_i , il,_ ,,liiil_ ....

,,:I' ' ,_:Llli-"_l_l_[I ""', 'i i . ' , '_I;IIPHII_'_",'f"! ....'"'- "i _

u"

- '','--'.!I o4. _iliiIi::_IHIII:"|1 _ .-4: ",-! lit .......... ; ..... I ,,,'---"

-- _ i lllll;;lllii!illl It111 _ "-'-II ! _i "_ "-"

_-" ' i ""

-- 0

• _ t_0-4 i ______4__' _ :i C

' , i iI , .> _ =i.l,=-

! i| N

-- " " "_i '"_ " ," / <-

'_ '.'.-I: , _',.,- ! , o_ r,---_- - _ - _

----_.,_i 25 --.-- _, I .-• ' i i II c/i i i ) . -t )l i.'

l.-. !i_ ;

id;i ti _ 1_ f

:":' ii!!ll!i :-'.111! ,. _li'" I i •ill;| II l,,_, ,-

; IE;I[i

_ll "•,.,. p ,I,,,!,. :'

I , . ,lllll,I i!tl"lt "il_lllti .

° Ill_li_!iI1 +

z 1 ___ I " " I " l _ I u I *= I < ']_i

r_i

i -,_,

] 974024] 03-0] 4

lines (thrusterremovedduringsuchoperations).A semi-opencanisterwas

mountedaroundthe thruster. Argonwas flowedthroughthe canisterto

reduceoxidationof the thrustercomponents.The thruster,thrustervalve

and filterwere securelyattachedto an aluminumplate. An insulatedand _

instrumentedthrusterassemblyfor sea-leveltestingis shown in Figure4.

:I A water showerheadwas installeddirectlyover the thrusterand valve assem-

bly as a precautionarymeasurein the eventof a propellantfire. The sea-

leveltestswere monitoredvisuallyby a closed-circuittelevisionhook-up

(controlblock-houselocated16 m from test ce11). The parametersrecorded

I duringsea-leveltestingwere the following: _..

i _ ManifoldPressure(PM).

_ InjectionPressure(PINJ)

ChamberPressure(Pc)

i

i _ NozzleTemperature(TN)

i il ' ChamberTemperature(TC)i InjectorTemperature(TINJ) i

i"-_', BarrierTube Temperature(TB) _

i : Valve Temperature(TV) f_" -' Il

I

. ,.,_ HeaterVoltage(VH)

HeaterCurrent(IH)

!i Valve Voltage(VV)

_ t! ValveCurrent(Iv)

°'_ /e

,_.,_,, The simulatedhigh altitudeperformancemeasurementswere conductedinfacilityincorporatinga 1.22m x 1.22m cylindricalvacuumchamber. High

vacuum(< 1.3 x lO"4 N/mZ) is maintainedby two 0.254m diffusionpumps. A

chevroncyro baffleis mountedat the inletport of each diffusionpumpand

is cooledwith liquidnitrogenduringoperation. The diffusionpump___m-

• bliesexhaustto a 38 !/s mechanicalpumpthrough5.1 cm tubing. The

6

L

i974024103-015

I*l,°

'"; Figure 4. Sea-Level Thruster-Valve Configuration

f,

q_

i

1974024103-016

mechanical pump is used in lieu of the diffusion pumps for steady-state

operation and high duty cycle pulsed-mode operation. The mechanical pump

maintains the chamber at a pressure of 130 N/m2 or less during such

operations.

The internal chamber configuration is shown in Figure 5. The chamber .."

contains two independent thrust and propellant supply systems (one system

was installed during this program reporting interval). The dual systems _._

satisfied the need to test more than one propellant without delays normally

encountered in changing propellants. A fully instrumenteddemonstration

thruster is ShOWn mounted on one thrust stand in Figure 6. The propellant °

, _ supply and mass flow measuring system is represented schematically in i

_ Figure 7. Dry, filtered nitrogen is used as the propellant pressurant.

: i The flow measuring device consists of a piston that displaces propellant

stored within a small diameter cylinder, lt,e piston displacement is

i • measured by a linear potentiometer.o

The data acquisition equipment in Figure 8 was used to obtain perfor-

mance data. Operating and performance data were recorded on an oscillograph

• or on magnetic tape. Three additional parameters were recorded for the

high altitude tests. They were thrust (steady-state)or integral of thrust

(impulse-bit in the case of pulsed-mode),mass flow and integral of chamber

. pressure.

Original performance measurements were acquired in British Engineering

units (foot-pound-second-degreeFahrenheit). The data in this report have

been conwrted to the International System of units (Sl) or to more conven-ient metric units. _

The thrusters were routinely disassembled and inspected throughout the

test program phase. Several screen pack assemblies were subjected to elec-

tron probe microanalysis for the identificationof deposits formed on the . _

screens during high temperature operation. :_.,,(3

2.2 CHEMICAL ANALYSES _ _

Standard analytical methods were used to determine the chemical compb- _

sition, particulate weight, particle size distribution and non-volatile

F_ residues for the propellants hydrazine, Aerozine-50, monomethylhydrazine,

8

1974024103-017

4

1974024103-018

Figure6. ThrusterMountedforPerformanceMeasurements

\

I! .

!l[,,i_

_ ,o __ io,'_'_,

1974024103-019

ll

1974024103-020

F

1974024103-021

and hydrazine-hydrazine azide. An analysis of the ammonia used for the mix- *

ture of hydrazine monopropellants (MHM) was supplied by the manufacturer.

, The chemical composition of the MHM propellant was determined by the

charging sequence. A pre-mixed and weighed charge of hydrazine and MMH ,_

was introduced into the piston tank. Both sides of the piston tank were

evacuated to remove a protective nitrogen blanket. Ammonia was transferred

to the propellant tank in the vapor phase and allowed to saturate the pre-

mixed hydrazine and MM.Hto the vapor pressure corresponding to an aqueous

solution content of 15 percent ammonia. Both ends of the propellant tank

were then sealed under pressure. --

Results of the propellant chemical analyses are presented in Tables 1

" _ through 4 for MIL-grade hydrazine, Aerozine-50, monomethylhydrazine,and

;_ hydrazine-hydrazine azide, respectively. The hydrazine azide content was

determined by potentiometric titration with 0.I N NaOHand ammonia liberated

from the addition of a weighed sample to acetone. The non-volatile residue

(NVR) for the hydrazine-hydrazine azide blend was determined by propellant

decomposition with hydrogen peroxide and slow evaporation on a hot plate to

dryness. The NVR contents of hydrazine, Aerozine-50 and MMHwere determined

by weighing the matter remaining after distilling I00 ml of propellant at

313°K and a pressure of 133 N/m2. The ammonia analysis appears in Table 5.

The NVR contents of hydrazine, Aerozine-50 and MMH were normal for these

" propellants. However, the high NVR content of the azide blend indicated

i that the propellant was contaminated. The non-volatile residues of the

_k four propellants were extracted with 3N HCl and subjected to atomic adsorp-

_ tion analyses for iron, nickel and chromium (major storage vessel constitu- "':_ents). The metallic contaminate level of the azide blend (Table 4) was I00 -_

to 200 times that of MIL-grade hydrazine (Table I). Altho_Jghhydrazine- '!

hydrazine azide propellants are more reactive than hydrazine, the large

difference in contaminate levels should be viewed with caution. The hydra- _.

zine test system and storage containers used during the evaluation test _

_ program phase were maintained _t the highest cleanliness levels applicable _

to TRW flight-_rientedprograms. The hydrazine-hydrazineazide blend had _'L_-,

been used on a previous program where t}=ecleanliness levels, storage and

handling methods were less stringent. The high azide blend contaminate

° level may have been due to prior handling.•. 13

i974024i03-022

Table I. Analysis of MIL-grade Hydrazine Propellant

(Ref. 4)RESULTS SPEC. LIMITS ANAL(SIS i_

=_ Density at 298°K, g/ml NR* 1.0047

Hydrazine, % 98 Min 99.50

Unknown, % NR trace

!, Water, % 1.5 Max 0.50 _'

i

2

• NO. OF PARTICLESPER I00 ml (Ref. 5) }

_, 6- I0 microns 9700 Max 361

: 1I- 25 microns 268_ Max 247t t

/ 26- 50 microlls 380 Max 1331".. _ *!

*L 51-I O0 microns 56 Max 9_- .

1 _ 101-250 microns 5 Max 0

-_ Fibers None None

_t _; Non-volatile Residue, _j/100 ml - 6.0. i

_ Element Analysis_ _PPmFe 0.26

._._,' Ni 0.09

_ Cr O.11

*NR: Not required

14

' _ r _

1974024103-023

Table 2. Analysis of Aerozine-50 Propellant

(50% N2H4 50% UDMH)

b

(Ref. 6) _-'i RESULTS SPEC. LIMITS A!'_-'LYSIS :_

Density at 296.9°K, g/ml NR* 0.8996

N2H4, % 51 * 0.8 51.58I-

UDMH, % 47 Min 47.81., 'I

Ammonia, % NF. trace _

mWater, % 1.8 Max 0.61

• NO OF PARTICLES _-CPER I00 ml ReLRe___,5_.]_) _!}

6 - lO microns 9700 Max 960 "_

il " 11 - 25 microns 2680 Max 320• ' 26 - 50 microns 380 Max 108

:i 51 - lO0 microns 56 Max 18

I _ lOl - 250 microns 5 Max l(_ None, Fibers None

I'

_ Non-Volatile Residue, mg/lO0 ml - 24.4

• _ Element Analysis, ppm

6 _ _2

• _, Fe O.79_.!, Ni 0.22

Cr 0.66

*NR: Not required

" 15

1974024103-024

Table 3. Analysis of MonomethylhydrazinePropellant

(Ref. 7 )RESULTS SPEC. LIMITS ANALYSIS

Density at 296.9°K, g/ml 0.870 to 0.874 0.8725

Monomethylhydrazine,% 98.3 Min 99.02

Unknown, % NR* trace

] Water, % 1.5 Max 0.98

rJ

NO. OF PARTICLES =_PER lO0 ml (Ref. 5)

! , w }

i 6 - lO microns 9700 Max 1460II - 25 microns 2680 Max 520

!26 - 50 microns 380 Max 122

_ 5! - lO0 microns 56 Max 31I

lOl - 250 microns 5 Max 4

i None NoneFibers

Non-Volatile Residue, mg/lO0 mg - 0.8

Element Analysis, ppm

Fe 0.39

Ni O.lO

_| Cr 0.03

*NR: Not Reouired

16

o

1974024103-025

T

t _,

I

Table 4. Analys:_ oT _"azine-Hydrazine Azide Propellant

RESULTS -,

" _ •

Density at 298°K, g/ml 1.0759

Hydrazine Azide, % 24.3B

WaKer, % trace .

, i

NO. OF PARTICLES (Ref.S) iPER I00 ml SPEC LIMITS ANALYSIS _

6 - I0 microns 9700 Max 1220 I_.

II - 25 microns 2680 Max 486 i

i : 26 - 50 microns 380 Max 130

,. 51 lO0 microns 56 Max 16

i"l' f: lOl - 250 microns 5 Max 5

_ _" Fibers None None

i _. Non-Volatile Residue mg/lO0 ml - 392.0

ii' _ Element Analysis, ppm", Fe 44.8

_ _ Ni 7.6g

L,e._',_i Cr 12.72

L- 17

1974024103-026

bTable 5. Analysisof AnhydrousAmmonia

I

Ammonia,% 99.99 Min °qW_

Non-BasicGas in Vapor Phase 25 ppm Max

Non-BasicGas in LiquidPhase lO ppm Maxi

, _ Water 33 ppm Max

Oil (as solublein petroleumether) 2 ppm Max

, Salt (calculatedas NaCl) None

Pyridine,HydrogenSulfide,Napthalene None

"r

18

1974024103-027

2.3 BASELINEPERFORMANCEDATA

The baselinedemonstrationthrusterconfiguration(FigureI) contained

sixty0.5 cm dia. platinumscreens(52 mesh,O.l mm wirediameter)and one

0.5 cm die.Haynes25 retainingscreen(40mesh, 0.28mm wire diameter).

The platinumscreenswere uniformlycompactedto 0.5 an depthand inserted _,

! intoa sleevehavingthe sameeffectiveinternallength. Performance

characterizatio,_and baselinetestingwith MIL-gradehydrazinewere performed

on fivedemonstrationthrusterspriorto operationwith the candidatemono-

propelIants• !

' Typicalthrusterpulsed-modecharact_.risticsare illustratedby the *"

chamberpressuretracesof Figure9 for inletpressuresof 1.034,1.379,and * .:: j

• 1.724MN/m2 with pulsedurationsof 25, 50, 75 and I00 milliseconds.The ;

• pulseratewas 2.5 Hz (onepulseevery 0.4 seconds). The traceat the top i

of each oscilloscopepicturerepresentsthe propellantcontrolvalvecurrent.

The deliveredspecificimpulse,rise_.Iddecay timesas a functionof pulse

width are presentedin Figu,_10. An injectionpressureof 1.724MN/m2 and : i

holding temperature of 810°K were used to obtain the performance parameters.• A more realistic pulse repetition rate of one per secondwas used. Conse- _._

quently, the temperatures indicated on Figure 10 are lower than those ofFigure9.

The bueltne steady-state performance characteristics In Figure 11 were

obtatned wtth a holding t_ereture of 810°K. The data were taken at maximum _,1_

operattPg temperatures whtch varied betmmn 1213 and 1238°K for the range of _*_tn|et pressures studied. Nomtnal design thrust of 0.344 N at 1.724 KN/m2

feed pressure was mt by a delivered thrust of 0.32 N. Chamberpressure

roughnessverted fr(R +__ to +6S amongthe ftve baseltne thrusters.

Tt_. s_eclftc _xllSe VaH_it_m betmmn the ftve besellne thrusters was -

' ' s nve.._--. (.._:_...- _ ' .. ,...... -: ,.• ..

'-_' _._-,_'/_ .., '_ i. ,., --' - " ' ' ":,.';,'" ">t,_"_-, '_" : ", ,

1974024103-028

°

,i

" ..... : PINJ= 1.034l_/m2

= m2* P = 0.172HI /cm\_'- _ " C

.... _.._._ .... i............ . ..... t = 20 ms/cm, H , lip

T = ]066°K' '% . C " "

f = 2.5Hz

__ P

F: ' P'NJL= I.379 MN/m

' ; 'l = 0.172 MN/m cm

I i

= T = 1033-II44°K _.

f = 2.5Hz :_

• jI' i

i.i " PINJ = 1.724MN/m2_ Pc = 0.172 MN/m2/cm

t = 20 mslcm -'

I

Tc = 1089-1144°K

_l ' f - 2.5 Hz

I b

. Figure9. BaselinePulsed-ModeCharacteristics

_, 20

1974024103-029

_ , |'nil ,_ v

5 "'

_'_E

INJECTIONPRESSURE= 1,724 _/m 2HOLDINGTEHPERATURE= 810°K

" PULSEPATE= ONEPERSECOND _ "

t

1.50E

z_: 1.25

,.n'n1.00 _ _,_

,.. 0.75 -.

= _I_ ",__- ,

"1-0.50

, m, _ ,

400

'; _ 300

"" 200 "I

1O0 l

ii ,

: IV

: 240 l l

1, HOLDING TEMPEHATURE = 810°K,,. 235

u

i t u._ 230, (,_ f

0.. .X ':

l " !i " 220

w 2151 ..

,o,i

="_ 2100.8 1.2 1.6 2.0 2.4 2.8

I INLET PRESSURE, MN/m2

F.?__

1974024103-031

(Figure12) was noticedon the top platinumscreen. The Haynes25 screen

(Figure13) retainedits structuraland chemicalintegrity. The deposit

was subjectedto electronprobemicroanalysis.A backscatteredelectron

micrographof the top platinumscreencenterappearsin Figure14. A

spectralanalysisof the X-rayse_Jctedwhen the electronbeamwas positioned

directlyon the depositrevealedthat the major cor,t_minateswere Fc, _i and

Cr. The relativeintensityof elementspresentare s:_mmarizedin Table6.

4 The Fe contentin the screencenterwas approximatelyfourto fivetimes

thatmeasuredon the outer peripheryof the top screen. An iron K X-ray jimage,Figure15, confirmedthat the irondetectedby the spectralanalysis

was localizedon the platinumscreen(Figures14 and 15 are of the same

!, region). The regionof highestcontaminationis at the lower rightof each i'k

figure.ri

" ' A spectralanalysisof the bottomHaynes25 retainingscreenrevealed

the presenceof W, Ni, Co,Fe, Cr, Mn and Si. The intensityof Fe-K radia-

tionfrom the Haynes25 screenwas considerablysmallerthan that obtainedfrom the top platinumscreen. Ironwas presenton both screenmaterialsin)

a disproportionateamountto that possiblypresentin Haynes25. The pre-

i ; senceof Ti in the top screendepositindicatedthat the causewas not due

!./ , to propellantattackand corrosionof the Haynes25 thrustermaterials. The

I logicalsourcesof contaminationare the stainlesssteelstoragevessels,

• i ? feedlines,filtersand propellantvalves. The nominalcompositionsof ,

k'_ _ stainlesssteelsused for propellanthandlingis given in Table 7. Haynes)

"" "" 25 is includedas a reference.J

; a The mechanismof the storagevesselmaterialdissolutioninto hydrazine(

"_I : has not beenwell defined. However,a very likelycause is the presenceof

• ( ' carbazicacid in propellantgrade hydrazine. Carbazicacidcan reactto form

•_ metal or hydrazinesalts,e.g., (N2H3CO0)3 Fe and N2H3COON2H5. These salts

.( , will be presentas residuesafterpropellantvaporization.The saltresidue

: may undergosubsequentdecompositionat the highthrusteroperatingtempera-

\ ; tures. Thiswould resultin a highlylocalizedmetallicconcentration.P

2.4 PROPELLANTCHARACTERIZATION

,,(i-'

_, This sectionpresentsthe operatingcharacteristicsof hydrazine-hydra-

•-_._ zine azide, Aerozine-50 and .nonomethylhydrazine with the baseline thruster, _ configuration(Sec.2.3). i,,Itialtestswith thesethreepropellantswere

_,_ _ performedunder sea-levelconditions. Initialcharacterizationtestswith

23

"t

4 - ,,'_

1974024103-032

Figure 12, Deposit on Top Platinum Screen

_ •" 4

] 974024 ] 0:3-0:3:3

......... _m l m

m

(b) 27X

Figure 13. Haynes 25 Retaining Screen!

"_ 25

I

] 974024 ] 0:3-034

I

t

-; %

Figure14. BackscatteredElectronImageof theTop PlatinumScreenCenter _"

i ',.i: 26

1974024103-035

Table6. SpectralAnalysisof PlatinumScreenDeposit

"

RELATIVEX-RAY INTENSITY

i'i

; Very.Strong Strong Medium Weak Trace

4 Pt Fe Cr Ti CaII ' Ni Co SiI

,I ' ci

'1• , Na_ I"-!

] i NOTE: Carbonbelow instrumentdetectionlimits.

i Oxygenbelow instrumentdetectionlimits.

)!

\!

5 '

t

1974024103-036

- :'_ _' I II " _ -- !",Iliiiliiiiiiiii Ii•, • I

II

50% MMH-50%N2H4 and MHM were performedduringthe laterstagesof theevaluationtest programwith thrusterconfigurationsderivecifromsatis-

. factoryoperationwith Aerozine-50.The test resultswith these propel-

lantsare includedin the performanceoptimizationsection• _I_

2.4.1 Hydrazine-HydrazineAzide

IA totalof 23.5minutessteady-stateoperationwas accumulatedbefore

testingwas terminatedBy an injectorfailure(revealedby post-testinspec- "_,

tion). The thrusterexhibitedmetastableoperationduringthi_ period•

Thismode is illustratedby the chamberpressuretrace in Figure16. Igni-

tion at the holdingtemperatureof IO00°Kwas very erratic. The large

chamberpressurefluctuationswere significantlyreducedwhen the energy:_' suppliedby decompositionraisedthe thrustertemperatureto I155°K.

; Chamberpressureroughnesscontinuedto decreasewith time. Highspeed

oscillographchamberpressuretrace_reproducedin Figure17 illustrate

, the roughnessdecrease.

Stab)eoperCtioncouldnot be achievedat injectionpressureabove0.83 MN/m."The injectionpressurewas reducedto 0.72MN/m2 and an addi-

• tional18 minutessteady-statetimewas accumulatedwhen an abruptlossof

chamberpressureoccurred. Operationduringthis periodwas characterized

._ by smoothand very roughbehavior• The chamberpressuretracejust priorto

and at injectorfailureis shown in Figure18. Post-testinspectionrevealed

that the injectorrupturedat the firstportionof the thermalreliefbend

(FigureIg).b_

i Disassemblyof the thrusterrevealeda considerableamountof screenpackrearrangementand compaction(Figure20). A two-zonedcontamination

regionis indicatedin the plan view (Figure20a). The individualscreen

wireswere bent and kinkedfromtheiroriginalgeometry. The obliqueview

in Figure20b illustratesthe screenpack compaction.Theseeffectswere

causedby the largechamberpressurefluctuationswhich occurredduringi

.-_ unstable_peration. _legligiblechambercorrosionwas observed, An interior

viewof the nozzleend appearsin Flgurp21a. The Haynes25 retaining

screen(Figure21b) remainedintactduringtesting.

An electronmicroprobeanalysisof th_ post-testscreenpackcondition

• indicatedthat the major contaminatewas iron. A backscatteredelectron

....I 30

I", I

197402410:3-039

! . _mat= / Lt_,

1974024103-040

...... II

..... i in ,, I | " ' '..... ". _ "= ...... + ..... _... in==__

--I :: -::_-._L-__ + --' _ !.- .4 ........... -I--...... '1- '-..... 1---.......... --4- ..... . ........ i -1- . ,

...... ' HEAD I --- -_ ............ <' ,, J _ • --I..... j ..... • _.; .,' l--- _ _. !---"+ i '" | ' "' ; _ '

.... r...... I .... "_ I_,, I \ u _ ;......... +., _+ ".... _,_ I

--:c ........ NOZZLE---- ' -_+ "- ".,[

.... _.... I" w• I

-_.+- _. -.-," ;............. I _ -_L T --J.... • . -'-_--:-+-----'+ ..... _u___- ______.

_ --+-+,-_-- _ l-- , :_-:_. --_--_ ----

++

"" ' I I I II.... u : "_I- I L

I '_ I nl .flit;i_ ++r ...... '--" II llllIO I .....

"' l II, llnlllll.:---- I IIIlJlllpl':ill :

i, ]I-_iI-- -- -- - +: IIII_

:_-- __ ....... _:__:.......___ --_._ ......... -;- _____ -___--__--.--- _. -_ +-- _ ..... i.....,+................. L.. o !

_!___ ,__ ,. , I o,,...___.___:_.___.:.,_ ___,._i_._L---__--140i-..... :-120! ......... 100i ..... .--,-RO-,_ .... --40:,-- ..... 2-0_ -d-_....4......... i-_'-----___ T"----_..... ",

...... T::-TIME, SECONDS---- ._ _ "--....

Figure 16. PreliminarySea-LevelSt_aei'- ::,_

StateOperationwith 76 Percent _rlydrazine--- 24 P_rcen_, _,

HydrazlneAzide |

I ....... - _ ' ' .................................

1974024103-041

_,'" 33

" k

w

1974024103-043

, _ Figure19. InjectorFailure

_, 34

.,,._., ._ _ ..... _, ___ -. ,,_h,iiimmaIi_%}

..... _. ., ........................... _ .................. _ ........ _

1974024103-044

Q

A

(a) Plan View i

I

Ik j

"_ L;: "_' Jt "I _ ....i

}- e=_ -

u

"; I_ (b) 0bliqueView

'i,tFigure20. Post-TestConditionof ScreenPack FromThruster

Operated on 76 Percent Hydrazine - 24 PercentHydrazineAzlde -_

! ,_ _ F

i

] 974024 ] 0:3-045

.J

¥

_ (a) Interior View of Nozzle End and Throat i

"2

i

, _

"z _ Ww

"' :,_f,,, (b) Haynes 25 Retaining Screen

Figure 21. Downstream Thrust Chamber Components of ThrusterOperated on 76 Percent Hydrazine - 24 Percent

I Hydrazine Azide

36

w

] 974024 ] 0:3-046

._ _ e'j_

imageof the centralareaof Figure20a appearsin Figure22. An Fe-K .:

X-ray imageof the same area is shown in Figure23. A spectralanalysis

also revealedthe presenceof chromium,nickeland cobalt. The ironcontent

was significantlyhigherthanthat observedon the hydrazinebaselinethrus-ter's screenpack.

2.4.2 Aerozine-50 _,I

A total of sevenminutessteady-stateoperationwas accumulatedwith

the baselinethrusterconfiguration.Injectionpressureswere variedbetween

0,31 and 1.03 MN/m2 and initialholdingtemperaturesof 993 and 1073°Kwere _, ',used. The thrusterexhibitedstableoperationunderall testconditions. )

|, Ignitioncouldnot be sustainedfor any reasonablelengthof timewith

: ' injectionpressuresabove0.31 MN/m2 at eitherholdingtemperature,Chamber I

' pressure(Pc)tracesduringsteady-stateoperationare illustratedin Figure24 for an injectionpressureof 1.03 MN/m2 and holdingtemperaturesof 993

i q and I073°K,respectively.Large chamberpressurefluctuationswere absent.

The gradualdecreasein P after two secondsrun timewas accompaniedby acdecreasein thrustertemperature(monitoredvisuallyon digitalreadout).

Limiteddecompositionoccurredat a low injectionpressureof 0.31MN/m2 for

about45 secondsbeforethe thrustertemperatureswere observedto decrease.

4: Post-testthrusterdisassemblyand inspectionrevealednegligiblecham-

. ber corrosion. C_rbondepositionwas not observedon the chamberwalls or

in the nozzlesection. No evidenceof carbondepositionwas noticedon the

platinumscreens. The bottomHaynes25 retainingscreenhad a darkdeposit

buildup. The top and bottomportionsof the screenpack appearin Figure

25. X-ray imagingin the electronmicroprobeconfirmedthat the depositon

the retainingscreenwas carbon.

2.4.3 Monome.th_lhydrazine

Preliminarysea-levelsteady-stateoperationwith MMH was similarto

i thatwith Aerozine-50.The rateof decreasein thrustertemperaturewas

more severethanthatwith Aerozine-50.This rapid performancedegradation

is illustratedin Figure26. Screenpackfloodingalso occurredat lower

injectionpressuresand higherholdingtemperatures.The onlydifference

was the timerequiredto producethe same levelof thrusterquench. The

1974024103-047

"°.4" ., -Y_ral

t.

," • J

.j-

I _ ;L ,_, o- "

|

i!

• , _

t !t1

e

!_ _. -_

Ftgure 22. BackscatteredElectron Imageof the TopPlatinum ScreenCenter FromThruster

• OperatedV;IthHydrazlne-Hydrazlne_Ide

"_ _" _ k ..... _ .......................................................

- ,, "- III I IIIII

\...... v _ .... _ .

1974024103-048

Figure23. IronK_ X-Ray Imageof the Top

PlatinumScreensof Figure22 _.

w,._,, .... , . _ , _ _,

] 974024] 03-049

1

,%,,

(b) Haynes25 RetainingScreen,20X

Figure25. Aerozine-50Post TestScreenPackAppearance@

41

1974024103-051

/

PROPELLANT:MONOMETHYLHYDRAZINE

INJECTIONPRESSURE= 0.68 MN/m2

HOLDINGTEMPERATURE= lO00°K

I000- -- I" ' "i 950-

l

o 6

• _ -05g 9oo-

,:4 850-,,,,,

( -03_)o, i

, -0.2 _ x800- _ k

-0.12.

ii ml mI * *! ! • ! I

' 16 12 8 4 0i_ TIME, SECONDS

Figure26. PreliminarySea-LevelSteady-StateThrusterOperationWithMonomethylhydrazlne

i "T:I 42 m ,,.

197402410:3-052

• I

steady-state tests were terminated prior to the condition of liquid propel-

]ant flow through the nozzle. The total steady-state operation amounted to

about five minutes.

The thruster was pulsed (50 ms pulse, one pulse per second) with an

injection pressure of 0.34 MN/m2 and holding temperatures of lO00, 1061

•_ and ll44°K, respectively. Two hundred pulses were accumulated at holding

temperatures of lO00 and 1061°K (one hundred each). There were no indica-

tions of abnormal operation at these temperatures. Rapid chamber pressure

degradation occurred after ten pulses at the high holding temperature of

!, l144°K. Post-test inspection revealed that the injectorwas plugged with

carbon. Thermal soakback between pulses was sufficient to cause vaporiza-

! _ tion and decomposition in the injector. No carbon deposits were observed

on any of the interior thrust chamber surfaces.

I-f ,

i_ _

.. i _ _

'_ L :_

i

1974024103-053

2.5 PERFORMANCEOPTIMIZATION

The initialcharacterizationtests (Section2.4) indicatedthat the

baselinethrusterconfigurationwas marginalfor stableoperal_ionwith thei

azide blendand inadequatefor operationwith the carbonaceouspropellants

:4 (AERO-50,MMH). Subsequenttestsrevealedthat the propellants'reactivity

in a thermalenvironmentdecreasedin the iollowingorder: Hydrazine-Hydra-

zine azide,Hydrazine,Aerozine-50,50% N!H4-50%MMH,MHM, MMH, This fact

I, requireda differentthrusterconfigurationfor each propellantin orderto ,L

i r accommodatethe varyingdecompositioncharacteristics.The resultingthruster

, configurationswere obtainedby varyingthe internalscreenpackgeometries.

The headand nozzlesectionswere not changed.

Eachnew thrusterconfigurationwas baselinedwith hydrazinepriorto

operationwith the candidatepropellant.A substantialamountof perfor-

t,__ i

"i " mance datawas gatheredfor operationwith hydrazine. One thruster 1!; configurationappearedto offer considerableperformanceincreasesover the

baselinethruster. A completeanalysisof hydrazineperformancewith the

"_" ' configurationsderivedfor operationwith other propellantswill appearasf

_j ( • a separatesectionin the Data Correlationportionof the FinalProject __

i Report. The data fromthose thrusterconfigurationsare presentedin this ,sectionfor comparativepurposes.

; 2.5.1 _Hydrazine-HydrazineAzlde

, The unstableoperationwhich led to an injectorfailurewith the

_,-L; baselinethrusterconfigurationindicatedthat undecomposedpropellant

traverseda considerablelengthof the screenpack. Subsequentdecomposi-

tion of this propellantcauseda pressurewave frontto rapidlymove towards

, the injectorend of the thruster. The intensityof thiswave frontpromoted

" 44

rapiddecompositionof propellantremainingin the head space. The end

resultof this processwas a laraepressurespike.

A series of tests wer_ initiated to determine the relationshipbetweenstablemodes of operation,screenpackdensityand characteristic

.. chamber length, L , Results indicated that the head space "reactivity"

controlsthe overallthrusterperformance.Two thrusterconfigurations W(_

which resulted in very unstable operation are briefly described, lhe con-

figurationswere the following: _ ,

_r I. Largehead space: 60 screenscompactedG.5 cm in a _L

0.75 cm sleeve•I-

2. highDensityScreenPack: 80 screensin a 0.5 cm sleeve,

standard head space, i_,.

Both thrusterconfigurationsresultedin unstabledecompositionin _he head

_ space;one by virtueof the largerphysicalvolumeand the otherby a larger! •I_ pressuredrop acrossthe screenpa_k•

A configurationusinga variabledensityscreenpack reducedthe

' i,_- _ head space "reactivity."_ixtyscreenswere packedin a 0•5 cm sleevewith_ _:

il the packingdensityat the headend approximatelytwicethatat the nozzle

_b_ i end. Stablesteady-stateoperationw_s obtainedat an injectionpressure

of 1 034 MN/m2 and a holdingtemperatureof 923°K. This representeda

i', _) considerableimprovementover the standardscreenpackgeometryfor which

., stableoperationwas marginalat a low injectionpressureof 0.717 MN/m2

and a holdingtemperatureof _g8°K. Slightinstabilitieswere observed _L_

after80 secondsof steadystateoperationbut largechamberpressuruvaria- ,_

i tionswere absent.

,i 4 Performancemeasurementswith hydra_inefor this thrusterconfigura-45

|

] 974024 ] 03-055

_ "'-_ °,4

tion were similar to the original baseline configuration. Values of

delivered specific impulse were five percent lower. Steady-state perfor-

measurements for the azide blend are given in Figt're 27.

A higher holding temperatureof 923_K was used after the start charac-

teristics at 8IO°K were rough. Chamber pressure roughness varied from�9":

at 1.034 MN/m2 injection pressure to _ 15:_it 1.724 MN/m2 injection pressure. Ww_

Operation at the high injection pressure of 2.413 MN/m2 resulted in metastable

operation similar to that obtained with the baseline configuration. The data _

at this injection pressure are approximate. The pulsed-mode performance.,

• characteristics_re presented in Figure 28. The low value of delivered

specific impulse and large rise time to 90% Pc for the 50 ms pulse indicated

• that vapc_izationwas occurring in the feed tube. i

2 5.2 Aerozine-50E

i " The inabilityto sustain steady-state ignition with the baseline con- !Ifiguration suggested that the thrust chamber resident times were too short.

I

z Residence times could be increased by a longer screen pack assembly (larger

L ) or by a higher pressure drop across an existing screen pack (baseline L ).

( The latter optlon was adopted. A 0.5 cm length sleeve was packed with 80

"i platinum screens. The free volume fraction within the pack was decreased

! from tl.ebaselinc configuration value of 0.576 to _.434. The thruster was

sea-level baseline tested on hydrazine and then operated with Aerozine-50.

Simulated high altitude performance measurements were later obtained with an

._._ identical thruster contigurationoperating with both propellants. -

i, Thirty minutes sustained steady-state ignition was obtained using

i Aerozine-50with the modified screen pack. An injection pressure of 1.034

4 MN/m2 and holding temperature of 810°K were used. The chamber pressureI •

46 _

'° b . . . _ .......

o

i

197402410:3-056

INLETPRESSURE,MN/m2mu

, Figure27. Hydrazlne-H_drazlneAzideSteady-StatePerfomance

-- 47

i"- I ..... I II nn_ ! n ................................................... 'i'"'r ..................

1974024103-057

35

U4._

2o-_ INJECTIONPRTSSURE= l.72414N/m2 -

HOLDINGTEMPERATURE= g23°K _:;

PULSE RATE= ONE PER SECOND _ •

25,.i

I--

,-_ 15

• lO

210

170, :-• LeL

50 75 1O0 •_"._

PULSEWIDTH,ms

i, t Figure28. Hydrazine-HydrazineAzide Pulsed-ModePerformance i

'_. -- 48 i,

1,

197402410:3-058

roughness was _ 3.5 percent at an average value of 0.637 MN/m2. The

chamber temperature rose to 977°K. The steady-state test was terminatedi

when response from the chamber pressure transducer became sluggish. At j!

this time, however, the thruster was still operating in a normal mode as _..

.', judged from the chamber temperature traces. The thruster was removed from _

the test stand and disassembled. The slow transducer response was caused

by a thin layer of carbon buildup in the nozzle section. The nozzle section

is shown in Figures 29a and 29b as internal and external views, respectively.l

!i , The nozzle throat showed no evidence of carbon accumulation; the pre and .

post-test diameters were identical. Carbon deposits were also observed on!-

the walls of the head space and within the screen pack. The injector showed

no signs of carbon buildup. The carbon deposited in the form of a fine

' powder.

. Steady-state performance parameters for Aerozine-50 are compared to

those for hydrazine in Figure 30 with the modified thruster configuration.

'- Temperature measurements indicated that considerable decomposition was

occurring near the nozzle. The nozzle block and chamber head temperatures

were 1061:K and I027°K, respectively (injectionpressure was 1.724 MN/m2).'W

The corresponding nozzle and head temperatures for operation with hydrazine ._

_:ere1205°K and 123g°K, respectively. Chamber pressure roughness was + 7% _'

I. for hydrazine and + 6% for Aerozine-50. "!m!" w

The pulsed-mode performance of hydrazine versus Aerozine-50 appears ._

in Figure 31. The operating parameters for these data were injection -:_

pressure = 1.724 MN/m2; holding temperature = 810°K; pulse rate = one per

second. The maximum thruster temperatures are indicated at each datum point.

An oscillograph recording of the pulsed-mode analog data is reproduced in

m

4g

t

' E_.IL_...'. ._ . . . _ ................ _ ......

.....",mmr • --,-_w, ............

]

i

i974024i03-059

Pressure Tap _ ,

_j. ?

T'"' '°:: i _, Heater Lead

(a) Interior View of Nozzle Section4 _lll

1 •!

8o

o

, el '4

(b) Exterior Vtew of Nozzle Section?

m

Figure 29. Post-Test Appearance of Nozzle SectionFromThruster Operated 30 Hlnutes

Steady-State With Aeroztne-50g

50 m

_:, _-_,._,_h " " " " " ' _' ' " ' _lm_mi,m_au, i,_ .........

1974024103-060

1.75

_s l. 50 1 . ,. • II ;,

'1' _ --, _- 1,00

lo.Ts0.5 ,, _';

CONFIGURATION:80 SCREENS,O.S cm SLEEVE" HOLDINGTEMPE_TURE = 810_K

#

:" 400 _.

, I 300i • 1.2

' =_ _ _,'." 200 _

i ,' • 100....

-I 22,=

220

, _ 215 " ' HYD '

_.} / AZlNEt:F 210

i 0.8 1.0 1.2 1.4 1_6 1.8 2.0 2.2 2.4 2.6r Figure 30. Steady-State Performance MeasurementsI,L , With Aeroztne-50;

"-_ 51

b , . , _

'1

197402410:3-061

|

INJECTIONPRESSURE-1.724 HN/m2 "HOLDINGTEHPERATURE" 810°KPULSERATE• ONEPERSECOND :,

200

107S°K_ "! 195

,' _ 190 -

-- 185 ,

_ _RAZINE d, _ 180 .,

175'" -q i

• a,,

• " AE_OZINE-50

, _ 165 _194°K ' "

16050 75 100

PULSEWIDTH,ms ..

i,

, i f '

_" :_,t

FlguPe 31. Pulsed-Hode Performance WithAerozJn_-50 "-"--

I

52 I_,

4

Figure32 for a lO0ms pulse. The rise and decay times to 90% and I0% PC/

were 28 ms and 75 ms, respectively.A 42 ms centroidshiftfrom the command

pulsewas calculated.

Post-testdisassemblyand inspectionrevealeda similarlevelof

carbondepositionas was observedafter sea-leveltesting.

2.5.3 Monomethylhydrazine

Attemptsto obtainsustainedsteady-statedecompositionwlth the,

Aerozine-50thrusterconfigurctionwere unsuccessful.A 1.02cm sleevewas

: packedwith 160 platinumscreensto providea higherscreenpack pressure

; drop (increasedresidencetimes). An additionalheaterelementwas wrapped

aroundthe longersleeveto preventtemperaturegradientsalongthe thruster

assembly. A separatepower supplywas used to equalizethe temperaturedis-

i tribution. Steady-stateoperationwas marginalat a holdingtemperatureof

I " ll98°Kand an injectionpressureof 1.034MN/m2. The nozzlesectiontemper-

ature rose to 1263 °K and the head quenchedto 773°Kafter fiveminutesof

operation. Longerrun times resultedin "flooding."Priorto this condition,I

the thrustlevelwas 154 mN with a deliveredspecificimpulseof 229 _ec.

i

, Hydrazinewas mixed in a l:l ratiowithMMH in o,'derto reducethe

high holdingtemperaturesnecessaryto initiateMMH decomposition.Two

screen_ackconfigurationswere used. One configurationwas similarto that

usedwith MMH. The 1.02cm sleevewas packedwith 180 screens. The secow_

)) thrusterhad 360 screenspackedin a 2.54cm sleeve. Marginalsteady-state

_ decompositionwas obtainedat a lowerholding temperaturec" I033°K with the

formerthrusterconfiguration.The thruster'stemperatut_-timehistoryindi-

cated that the decompositionfrontwas towardsthe noz= nd. Sustained

steady-statedecompositionwas obtainedfor ten minutesw_h the mn9 (:'54 cm)

53

-_JL ..... . ...... _ .................. - ,__ .............................

1974024103-063

1974024103-064

Q

screenpackassemblyat a holdingtemperatureof I033°Kand injectionpres-

sureof 1.034MN/m2. Thrustand chamberpressuredegradationwere noticed

after ten minutes. The thrustdecreasedfrom 168 mN to 52 mN. The specific >

impulsedecreasedfrom22l sec. to 206 sec. A decreasein thrustertempera- _

ture from ll43°Kto I083°Kwas recorded. Duringthrustdegradation,the(

primarydecompositionfront appearedto move fromthe middleof the screen

pack to the headend. These observationsindicatedthata highpressure

dropwas createdin the nozzlesection. Post-testinspectionrevealeda .

substantialcarbondepositon the Haynes25 retainingscreen. HeavycarbonYA depositswere not noticedelsewhereon the internalthrustchambercomponents,

j-

Pre and post-testinjectorwater flow characteristicswere identical. It was

concludedthat the thrustdegradationwas causedby carbonbuildupon the _t

Haynes25 retainingscreen.

• Limitedpulsed-modedata was obtainedfor the 50/50N2H4-MMHmixture

with the 2.54 cm screenpack. A specificimpulseof 171 sec.was obtained

i,_ for a lO0 ms pulseat a hol ;ngtemperatureof I033°Kand an injectionpres-

" MN/m2.,,. sureof 1.034 The pulseratewas one per second;the thruster

temperaturerose to I08_°K.i

t#

_ 2.5.4 Mixtureof HydrazineMonopropel]ants

i

i' The MHM blendwas the lastpropellai,_Inve:i_Igatedduringthe eva- ,I

luationtest program. Previoustestswith Aerozine-50,MMH and the N2H4 -°;

,N_IHmixtureindicatedthatworthwhiledata would not be obtainedusingthe)

,:IF baselinethrusterconflguraL_on.Accordingly,longerscreenpackassemblies , ,_:'_:were used to charactev.lzethe MIIMblend. The 180 screen,1.02cm sleevewas _

usedto obtaindata for comparisonwith MMH and 50% N2H4 - 50%MMH. Them_

• final configuration consisted of 400 screens in a 2.S4 cm sleeve. Both _t

i

1974024103-065

thrusterconfigurationswere steady-statebaselinetestedwith hydrazine.

The steady-statebaselinecharacteristicsare shown in Figure33. Very

high thrusterhead temperatureswere recordedduringthese tests. The

thrustertemperaturesas _ functionof inletpressureare shown in Figure34.

A holdingtemperatureof I143°Kwas necessaryto sustainMHM decompo- _-

sition with the shorter screen pack (180 screens, 1.02 cm sleeve) at an ,,_

injectionpressureof 0.965 MN/m2. Operationat higherinjectionpressures

resultedin "flooding." The steady-statedata in Figure35 showsperformance!,

degradationat an injectionpressureof 1.655MN/m2. The nozzl=and headr

_! , sectiontemperaturesremainedat the holdingtemperaturewhile the middle

; screenpacktemperaturerose to 1223°K. Fifteenminutessteady-stateopera-

¢ tionwas accumulatedvith the 1.02cm screenpack. Post-testdisassembly) ' revealeda minimalamountof carbondeposition.Carbonaccumulationwas

i not observedin the head spaceor on the platinumscreens. Littleto no

• " carbonwas noticedin the nozzlesection. However,a smalldepositwas

: noticed on the Haynes 25 retaining screen.l

; Operationwith the 2.54on sleevecontaining400 platinumscreens,o

_ _' resulted in a reduced holding temperature necessary to initiate and sustain

i _i';' MHMdecomposition. The holding temperature was reduced from 1143°K to 1033°K.i + The maximumthrustertemperature(I0940K)at an injectionpressureof 1.034

I : MN/m2 occurredat the middleof the screenpack. The decompositionfront

moved towardsthe nozzlesectionas the injectionpressurewas increased.Atk

• 1.724MN/m2 injectionpressure,marginal operationresulted. At higherinjec-

qL_ tlonpressures,decompositioncouldnot be maintainedand "flooding"occurred.

,, Post-test thruster inspection revealed little carbon deposition. Steady-

,':'_, state performance data for tha 2.54 cm screen packconfiguration appears in

Figure 36. Pulsed-modedata at an injection pressure of 0.81 MN/m2 were!

56

t

...,,j JM _' m I ......

1974024103-066

_ 1.00......i

°,s_ ,_

| o.2s _

Holdlr,g Temperature= 1143°K !

180 Screen_,1.02 cmPack _ ,

i I _ }li 4o0 i

*n 300

200

. ril,_ _00

1i "

201 ....u

. 21111 "

I - ,4_

195, .:_0.9 1 0 1.1 1 2 1 3 1 4 1'.5 1.6 1.7

Inlet Pressurs, _/m 2

t Ftgure 35. MHHSteady-StatePerfoPmancewtth 1.02 cmScreenPack

59

. t _-i

1974024103-069

] .25

i. 1.00 .. _- I " ''-. _ .

0.75 _w

_ 0.50" HOLDINGTEHPERATURE= 1033°K ""4

r 400 SCREENS,2.54 cm PACK ,

L

" 3O0

a ::3

" i

i ° m, •

!

]

"" 220

_ °

; _ 215

"' 210i205

• _ _

2_' -., .8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 --i ,:_. INLETPRESSURE,mira2 '_.

L.._._-!

" i FIgure 36. HHMStea_-State Perfomance 14tth2,54 an Screen Pack

--] T 60

1974024103-070

t

obtainedfor pulsewidthsof 75 and 100 ms. The deliveredspecificimpulse

at 75 ms was 162 sec.and 174 sec. for the lO0 ms pulse. The riseand

decay timeswere slightlylongerthan thoseobservedfor Aerozine-50.

't

1974024103-071

I

3.0 DISCUSSIONOF RESULTS

3.! BASELINEPERFORMANCE

The steady-stateand pulsed-modeperformancecharacteristicsfor the _

standard60 screen0.5 cm sleevewerecomparableto thoseobtainedwith the .

•_ EHT (2). The additionalthrustchamberand nozzlemass associatedwith

the modular,three piecedesignincreasedthe timesto reachholdingand

steady-statetemperatures.Holdingpowerlevelsof 8 to g.l wattswere i

_ requiredto maintainthe thrustertemperature_t BIO°Kunder simulatedhigh i'-@

; altitudeconditions.The powerrequirementfor a flightconfigurationthrus-

ter with properinsulation,no pressuretap and only one heaterlead has

been previouslydemonstratedto be lessthan 5 watts (2).

Hydrazineperformancemeasurementswith the modifiedscreenpacksr

indicatedthat the baselineconfiguration(60 screens,0.5 cm sleeve)was ,

" non-optimal.Comparativedata on fourconfigurationsare presentedint

Table 8. The data are for steady-stateat an injectionpressureof 1.724

"'If MN/m2 and a holdingtemperatureof 810°K. A 3.5% increasein delivered.!

•) specificimpulsefor the largehead spacethrusteroverthe baselineconfig-

I urationis significant.The higherthrusterheadtemperatureswith the

,.tL_

modifiedconfigurationssuggestedthat homogeneous,gas phasedecomposition _k

_, kineticswere promotedin the headspace. The lowerperformancelevelsof

• _ the longerscreenpackconfigurationsindicatedthat substantialamountsof' iiammoniawere dissociatedwithinthe screenpack. Thiswas reflectedby a

decreasein nozzletemperaturewith an increasein screenpack length "

(mediumversuslongscreenpack). The pulsed-modeperformancelevelsalso .:_,

decreasedwith the longerscreenpackconfigurations.

(

62

._ .14JJ _ i

1974024103-072

m

.J

3.2 CANDIDATEMONOPROPELLANTS

A comparisonof the delivere.4 steady-statespecificimpulsefor the

candidatemonopropellantsis presentedin Figure37. The configurations

and holdingtemperaturesfor each propellantare summarized. Reference

data for hydrazineare included. The generalperformancelevelsare in

reasonableagreementwith the predictionsof the AnalyticalTask Summary

Report(1) exceptthe datum pointfor MMH. The highholdingtemperature

, (IIgB°K)resultedin a somewhatinflatedspecificimpulsevalue. The

; steady-stateprogramgoalof 200 sec.specificimpulsewas met by all2

: propellantsstudied. A similarcomparisonof the pulsed-modespecific

impulseappearsin Figure38. Largedifferencesin steady-stateand pulsed-

mode performancelevelsfor shortand long (or highdensity)screenpacks

by comparingFigures37 and 38. The 1'atiosof pulsed-modetoare apparent

;/ steady-statespecificimpulsefor 75 and lOO ms pulsesare presentedin

Table 9. Pulsed-modeperformancefor Aerozine-50and MHM was compromisedj

"' _'" in orderto obtainadequatesteady-stateoperation. Longeror higher( ),

- "; densityscreenpack assemblieswere requiredto satisfythe heattransfer

conditionsnecessaryto initiatedecompositionof the carbonaceouspropellants.

' _I : The ease of initiatingdecompositiondecreasedin the followi,lgorder:

) Aerozin__-50,50% N2H4-50%_IH, MHM and MMH. Sustainedsteady-stateoperation

with Aerozine-50(50%N2H4-50%UDMH)was obtainedwith an 80 screen,0.5 cm

'" screenpack at a 81O°Kholdingtemperaturewhereasa long screenpack (360

. screens,2.54cm sleeve)and I033°Kholdingtemperaturewere requiredto de-

_ composethe 50% N2H4-50%MMH propellant.The additionof hydrazineto UDMH• " and MMH effectivelyreducesthe holdingtemperaturenecessaryto initiate

_!_ pureUDMH or MMH decomposition.The energyliberatedby hydrazinedecompo-

i:/ _ sitionis made availableto assistUDMH or MMH decomposition.

,T_i . ' |

i974024103-074

CONFIGURATIOH HOLDING_ SCREENS _$.J,_E__ TEMPERATURE,°K

Azide 60 0.5 923 !_AERO-50 80 0.5 810 '

( MHM 400 2.54 1033

50 NzH4 - 50 MMlt 360 2.54 1033 "

MMH 160 1,02 1198

N2H4 60 O.5 810I

t

1

240 ( _ _i 1

' i; _ 235 )Azide

l

• 230 _ N2H4--,. T

O_ '

225 _RO-50 __t,,#}

215 _ I" "MHM

210 - -

205

i i

2000.8 1.2 1.6 2.0 2.4 2.8 4,_

INLETPRESSURENN/m2 :::_:':

Figure 37. Steady*State Perfomance Data of Five

( Candidate Monopropellants

1974024103-075

|

INJECTION_RESSURE HOLDINGTEMPERATUREPROPELLANT _ MN/m_ °K

HA 1.724 923

MIIM 0.807 1033AERO-50 1.034 810

50 N2H4 - 50 _ 1.034 1033

Hydraztne ' 1.724 810

(PULSERATE- ONEPERSECOND) *'_

1i _' -210 ......

' 205

200

m 190

= 185

,.., 1

D. 175

N2N4-

155 AERO-50

150 HHM50 75 100

PULSE-WIDTH,ms

Figure 38. Pulsed-Hode Performance Data of Four( Candtdate Honopropellants

66

,_' (

I I ' I

1974024103-076

II

1974024103-077

J

i

Carbondepositedon the Haynes25 retainingscreenin a dispropor-

tionateamount to that observed on the other interior thrust cham_er

components,A strikingexampleof thisbehavioris noticedin Figure25

(Aerozine-50,preliminarysea-levelcharacterization).Carbondeposited ._

"t only on the Haynes 25 retaining 5cr __. The heat transfer characteristics

1 in the vicinityof the retainingscreen:_ouldnot be sufficientto cause ._

localized propellant decomposition. A logical explanation would be a

I higherlevelof catalyticactivityof Haynes25 than thatof platinum, _ .

I i

!

r_

J

!' ii,_

l- 68

I.

1974024103-078

f

4.0 NEW TECHNOLOGY

The electrothermalthrusterconcepthas beendemonstratedto be

feasiblefor operationwith propellantsotherthanMIL-gradehydrazine.

The modulardesignof the monopropellantdemonstrationthrusterallowed 1

" _, the rapid evcluationof car,didatepropallantsat significantcost savings,

A secondarytaskof the EvaluationTest Programwas to obtainbase-

linehydrazineperformancedata for all new thrusterconfigurations.One

' !..r' thrusterconfigurationprovidedsubstantialperformanceincreasesover

_ previouselectrothermalhydrazinethrusters, The data generatedfromthe ,

, severalconfigurationsare amenableto analyticalinvestigationwhichwill

increasethe level of understandinghydrazinedecompositionprocesses. !

I

5.0 PROGRAMFOR THE NEXTREPORTINGINTERVAL/

The work scopeduringthe nextreportingintervalincludesthe Final

ProjectReportpreparation.An integralpart _f that reportis the Task IV I_

Data Correlationphase. The Data Correlationobjectiveis to propose _" .

specificreco_endationsfor the work requiredto designand developflight

worthyelectrothermalthrustersusinglow freezingpointmonopropellants _ -

for spaceflightapplications.Resultsof the Tasks II and Ill phaseswill

ibe criticallyreviewedand _nalyzedin orderto fomulate a development _ '

/, programto meet the Task IV objective. _i

1

'I,|

1I

•i !

1974024103-080

6.0 CONCI.USIONS

The electrothermalthrusterdesignedfor operationwith MIL-grade

hydrazineis suitablefor operatior,_vithpropellantshavinglowerfreezing j_

points. Internalthrustchambermodificationswere requiredto accommodate .

the differentdecompositioncharacteristicsof each propellant.The pro- -

pellant'stendencyto readilydecomposein a thermalenvironmentdictated

_heextentof modification.All modificationswere performedon the screen

packassembly;the head end and nozzlesectionwere unchanged. The

i_, propellants'reactivitydecreasedin the followingsequence: 76% N2H4 -

: 24%N5H5> N2H4 > Aerozine- 50 > 50% N2H4 - 50% MMH > MHM > MNH. The

inductiontime to initiatedecompositionwas increasedby additionsof UDMH{

! _ and MMH to hydrazine. Thrusterconfigurationsemployinglongerand/or ,

i higherdensityscreenpackswere requiredto obtainsteady-statedecomposi- :

1

q tion. The programgoal of 200 sec. steady-statespecificimpulsewas

. exceededby all prope]lantstested. The pulsed-modeprogramgoal of 175

i sec.was exceededby the azide blendfor pulsewidthsgreaterthan50 ms and

was met by the carbonaceouspropellantsfor pulse widthsgreaterthan lO0ms.

A substantialamountof thermalenergymust be suppliedto initiate%

_ decompositionof propellantscontainingUDMH and MMH. The rate controlling '_i stepappearedto be the endothermicremovalof methylradicals. Propellants !

I containingMMH requiredgreaterheat inputthan thatcontainingUDMH.

_ I' Carbondepositionfrom the TRW-formulat_mixture(MHM)was minimal. ,/'i

Carbonaccumulationresultingfrom long_erm operationwith Aerozine-50 "_,

may resultin performancedegradationwith the configurationderivedfor ,_

its operation. An appraisalof detrimentalcarbondepositionresulting

J( from 50% N2H4 - 50% MMH decompositionwas maskedby the apparenthigh

1974024103-081

lcatal;,ticactivityof the Haynes25 retainingscreen.

The originalbaselineconfigurationgave non-optimalhydrazine

' performance.Performancewas increasedby promotinghomogeneous,gasW_

phasedecompositionkineticsin a largerhead space.

, The EvaluationTest Programresultsindicatedthatthe basic i

thrusterconceptwas applicableto the severelmonopropellants.However, i,._

the thrusterconfigurationsfor specificpropellantswill differin order

to yield optimumperformance. _ '

#

=!o

iI

i

i l72

1974024103-082

(

7.0 RECOMMENDATIONS

The processof nntimizingperformanceconcentratedon the internal

screenpack geometry. Methodsof increasingresidencetimes in the head _%

space should be invest'gated for the carbonaceous propel]ants. This would

" reduceheatlossesassociatedwith the longscreenpacks. Alternateinjec- i

tion techniqueswhich could renderthe incomingpropellantstream_mstable _ ,appeardesirable. The net effectwould increasethe surfaceto volume

ratio and allow a greaterquantityof heat to be transferredto the propel- i_',

_4 lantat injection. : ..-" !

T,_. i_rgehead space _nrusterwhich gave c,,-_r,ur_._,,performancewith i

i hydrazi_._:._t.:.,,.,.be fullyexploited. _ :k

!1i

i

1

t r,_:

'i73

1974024103-083

"4 •4_

8.0 REFERENCES

I. KuenzIj,J. D. and R. Grabbi. "Studyof Monopropellantsfor Electro-

thermalThrusters,AnalyticalTask SummaryReport,"TRW SystemsGroup,

RedondoBeach,Califernia,ReportZz4og-6oIO-RU-O0,December1973.

2. "MonopropellantHydrazineResistoje*, EngineeringModel Fabrication

and Test Task SummaryReport,"TkW SystemsGroup,RedondoBeach,

California,Report20266-6024-R0-00,March 1973.

3. Kuenzly,J. D. "Studyof Monopropellantsfor ElectrothermalThrusters,

Dp_gn and F.,,-icationTask SummaryReport,"TRW SystemsGroup,Redondo

Beach,Calif,nia,Report22409-6012-RU-00,January1974.

' 4. "Propellant,Hydrazine,"MilitarySpecificationMIL-P-26536C,May 1969.

|c

5. "Cleaning and Packiag of Fluid System Components," TRWSystems Group,

Rc_ondoBeach,California,SpecificationPR2-2,Table I, Level2.i -i

i

i 6. "_:.-ope_,lant,Hydrazine-uns-D'methylhydrazine(50%N2H4-50%UDMH),"

_i "i tary Speci fice.ti on MIL-P-27402B.

7. "Propellant,Monomethylhydrazine,"MilitarySpecificatio,P;L-P-_.)'404A,

Amendment2, June 1970.

_ "_ .,_

_'_" _

.q

I

'l

_ 4

, t

74

_'

1974024103-084